packages feed

avers (empty) → 0.0.1

raw patch · 12 files changed

+2829/−0 lines, 12 filesdep +MonadRandomdep +aesondep +attoparsecsetup-changed

Dependencies added: MonadRandom, aeson, attoparsec, base, base16-bytestring, bytestring, containers, cryptohash, inflections, influxdb, mtl, network, resource-pool, rethinkdb-client-driver, scrypt, stm, template-haskell, text, time, unordered-containers, vector

Files

+ LICENSE view
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+ Setup.hs view
@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain
+ avers.cabal view
@@ -0,0 +1,61 @@+name:                avers+version:             0.0.1+license:             GPL-3+license-file:        LICENSE+author:              Tomas Carnecky+maintainer:          tomas.carnecky@gmail.com+category:            Avers+build-type:          Simple+cabal-version:       >= 1.10++synopsis:            empty+description:         empty+++library+    hs-source-dirs:   src+    default-language: Haskell2010++    ghc-options:+        -threaded -Wall+++    -- For the time being everything is exported.+    exposed-modules:+        Avers+      , Avers.Metrics+      , Avers.Patching+      , Avers.Storage+      , Avers.Storage.Backend+      , Avers.Storage.Expressions+      , Avers.TH+      , Avers.Types+      , Avers.Views+++    -- Standard dependencies, stuff that is or should be in the platform.+    build-depends:+        aeson+      , attoparsec+      , base <= 9999+      , bytestring+      , containers+      , mtl+      , network+      , stm+      , template-haskell+      , text+      , time+      , unordered-containers+      , vector++    -- More exotic dependencies which people may not immediately recognize.+    build-depends:+        MonadRandom+      , base16-bytestring+      , cryptohash+      , inflections+      , influxdb+      , resource-pool+      , rethinkdb-client-driver >= 0.0.11+      , scrypt
+ src/Avers.hs view
@@ -0,0 +1,107 @@+{-# LANGUAGE NoImplicitPrelude #-}++module Avers+  (+    -- * The Avers Monad+    Avers+  , evalAvers++    -- * Types+  , Path(..)+  , Pk(..)++  , ObjId(..)+  , rootObjId++  , RevId(..)+  , zeroRevId++  , ObjectId(..)+  , Operation(..)++    -- * Object+  , Object(..)+  , exists+  , createObject+  , lookupObject+  , deleteObject+  , pruneObject+  , objectsOfType+  , allObjectsOfType++    -- * Patch+  , Patch(..)+  , PatchError(..)+  , lookupPatch++    -- * Snapshot+  , Snapshot(..)+  , lookupLatestSnapshot+  , objectContent++    -- * Release+  , Release(..)+  , lookupRelease+  , createRelease+  , lookupLatestRelease++    -- * Patching+  , resolvePathIn++    -- * Session+  , SessionId(..)+  , Session(..)+  , saveSession+  , lookupSession+  , dropSession++  , ObjectType(..)+  , SomeObjectType(..)+  , lookupObjectType++  , AversError(..)+  , AversConfig(..)+  , AversState+  , newState+  , strErr+  , parseValueAs++    -- * Blob+  , BlobId(..)+  , Blob(..)+  , createBlob+  , lookupBlob++    -- * Secret+  , SecretId(..)+  , Secret(..)+  , updateSecret+  , verifySecret++  , applyObjectUpdates+  , runQuery+  , runQueryCollect+  , parseValue+  , parseDatum+  , newId++  , objectsTable+  , blobsTable++  , validateObject++    -- * Views+  , View(..)+  , SomeView(..)+  , viewTable+  , updateView++  ) where++++import Avers.Patching+import Avers.Storage+import Avers.Storage.Backend+import Avers.Types+import Avers.Views
+ src/Avers/Metrics.hs view
@@ -0,0 +1,39 @@+{-# LANGUAGE TemplateHaskell            #-}+{-# LANGUAGE OverloadedStrings          #-}++module Avers.Metrics where++import           Control.Concurrent+import           Control.Monad.State++import           Data.Text (Text)++import           Network.BSD++import           Database.InfluxDB+import           Database.InfluxDB.TH++import           Avers.Types+++data Point = Point+    { pointMachine   :: String+    , pointComponent :: Text+    , pointValue     :: Double+    }+++reportPoint :: Text -> Double -> Avers ()+reportPoint series value = do+    ac <- gets config+    case influxConfig ac of+        Nothing -> return ()+        Just cfg -> void $ liftIO $ forkIO $ do+            h <- getHostName+            postWithPrecision cfg "rmx" SecondsPrecision $ withSeries series $ do+                writePoints $ Point h "api" value+++deriveSeriesData defaultOptions+  { fieldLabelModifier = stripPrefixLower "point" }+  ''Point
+ src/Avers/Patching.hs view
@@ -0,0 +1,223 @@+{-# LANGUAGE OverloadedStrings #-}+{-# LANGUAGE RecordWildCards #-}++module Avers.Patching+    ( applyOperation+    , opOT+    , rebaseOperation+    , resolvePathIn+    ) where+++import           Data.Monoid++import           Data.Text (Text)+import qualified Data.Text as T++import qualified Data.Vector         as V+import qualified Data.HashMap.Strict as M++import           Data.Aeson+import           Data.Aeson.Types++import           Avers.Types (Patch(..), Path(..), Operation(..), PatchM, PatchError(..))++import           Control.Monad+++-- | Apply the given op on the value. Can throw an exception if the operation+--   is invalid.+applyOperation :: Value -> Operation -> PatchM Value+applyOperation value Set{..} = changeObject value opPath $ \key ->+    maybe (M.delete key) (M.insert key) opValue++applyOperation value Splice{..} = changeArray value opPath $ \a -> do++    -- Check if the indices are within the allowed range.+    when (V.length a < opIndex + opRemove) $+        Left $ UnknownPatchError $ mconcat+            [ "Index out of range ("+            , T.pack (show $ V.length a)+            , ","+            , T.pack (show opIndex)+            , ","+            , T.pack (show opRemove)+            , ")"+            ]++    -- The existing array and the elements we want to insert must match+    -- structurally (have the same type). Furthermore, if the array consists+    -- of objects, each object is required to have an "id" field.+    unless (isStructurallyEquivalent opInsert a) $+        Left $ UnknownPatchError "Array doesn't match structure"++    return $ V.take opIndex a V.++ V.fromList opInsert V.++ V.drop (opIndex + opRemove) a++  where+    isStructurallyEquivalent :: [Value] -> V.Vector Value -> Bool+    isStructurallyEquivalent a b = strings a b || validObjects a b++    strings      a b = all isString    a && V.all isString    b+    validObjects a b = all hasObjectId a && V.all hasObjectId b+++isString :: Value -> Bool+isString (String _) = True+isString _          = False++hasObjectId :: Value -> Bool+hasObjectId (Object o) = M.member "id" o+hasObjectId _          = False++pathElements :: Path -> [Text]+pathElements = T.split ('.' ==) . unPath++changeObject :: Value -> Path -> (Text -> Object -> Object) -> PatchM Value+changeObject value path f = changeObjectAt value (init (pathElements path)) $ \x ->+    case x of+        Object o -> Right $ Object $ f (last (pathElements path)) o+        _        -> Left $ UnknownPatchError "Can not change a non-object"++changeArray :: Value -> Path -> (Array -> PatchM Array) -> PatchM Value+changeArray value path f = changeObjectAt value (pathElements path) $ \x ->+    case x of+        Array a -> fmap Array $ f a+        _       -> Left $ UnknownPatchError "Can not change a non-array"+++changeObjectAt :: Value -> [Text] -> (Value -> PatchM Value) -> PatchM Value+changeObjectAt container [] f = f container++changeObjectAt (Object o) (x:xs) f =+    case parse (const $ o .: x) o of+        Error   _ -> Left $ UnknownPatchError $ "Key '" <> T.pack (show x) <> "' does not exist inside the object"+        Success a -> do+            new <- changeObjectAt a xs f+            return $ Object $ M.insert x new o+++changeObjectAt (Array a) (x:xs) f =+    case V.findIndex (matchObjectId x) a of+        Nothing    -> Left $ UnknownPatchError $ "Can not find item with id " <> T.pack (show x) <> " in the array"+        Just index -> do+            new <- changeObjectAt (a V.! index) xs f+            return $ Array $ a V.// [(index, new)]++changeObjectAt _ _ _ = Left $ UnknownPatchError "Can not descend into primitive values"+++matchObjectId :: Text -> Value -> Bool+matchObjectId itemId (Object o) = Just (String itemId) == M.lookup "id" o+matchObjectId _      _          = False++++-- | Resolve the path in the object.+resolvePathIn :: Path -> Value -> Maybe Value+resolvePathIn path = go (pathElements path)+  where+    go []     value      = Just value+    go [""]   value      = Just value++    go (x:xs) (Object o) =+        case parse (const $ o .: x) o of+            Error   _ -> Nothing+            Success a -> go xs a++    go (x:xs) (Array a)  =+        maybe Nothing (go xs) $ V.find (matchObjectId x) a++    go _      _          = Nothing++++-- Set (foo)        -> Set (foo)        = ok+-- Set (foo)        -> Set (foo.bar)    = drop+-- Set (foo.bar)    -> Set (foo)        = ok+-- Set (foo)        -> Set (bar)        = ok+--+-- Set (foo)        -> Splice (foo)     = drop+-- Set (foo)        -> Splice (foo.bar) = drop+-- Set (foo.bar)    -> Splice (foo)     = ok+-- Set (foo)        -> Splice (bar)     = ok+--+-- Splice (foo)     -> Set (foo)        = ok+-- Splice (foo)     -> Set (foo.bar)    = ok if foo.bar exists+-- Splice (foo.bar) -> Set (foo)        = ok+-- Splice (foo)     -> Set (bar)        = ok+--+-- Splice (foo)     -> Splice (foo)     = drop -- todo: ok (adjust)+-- Splice (foo)     -> Splice (foo.bar) = ok if foo.bar exists+-- Splice (foo.bar) -> Splice (foo)     = ok+-- Splice (foo)     -> Splice (bar)     = ok++opOT :: Value -> Operation -> Operation -> Maybe Operation+opOT content base op++    -- Duplicate ops are dropped.+    | base == op = Nothing++    -- If neither is a prefix of the other (they touch distinct parts of the+    -- object) then it's safe to accept the op.+    | not ((opPath base `isPrefixOf` opPath op) || (opPath op `isPrefixOf` opPath base)) =+        Just op++    | otherwise = case base of+        Set{..}    -> setOT opPath+        Splice{..} -> spliceOT opPath++  where+    setOT path = case op of+        Set{..} -- Set -> Set+            | path == opPath             -> Just op+            | path `isPrefixOf` opPath   -> Nothing+            | otherwise                  -> Just op++        Splice{..} -- Set -> Splice+            | path == opPath             -> Nothing+            | path `isPrefixOf` opPath   -> Nothing+            | otherwise                  -> Just op++    spliceOT path = case op of+        Set{..} -- Splice -> Set+            | path == opPath             -> Just op+            | path `isPrefixOf` opPath   -> onlyIfPresent opPath+            | otherwise                  -> Just op++        Splice{..} -- Splice -> Splice+            | path == opPath             -> spliceOnSplice base op+            | path `isPrefixOf` opPath   -> onlyIfPresent opPath+            | otherwise                  -> Nothing++    onlyIfPresent path = case resolvePathIn path content of+        Nothing -> Nothing+        Just _  -> Just op++    (Path a) `isPrefixOf` (Path b) = a `T.isPrefixOf` b++    -- Both ops are 'Splice' on the same path.+    spliceOnSplice op1 op2+        | opIndex op1 + opRemove op1 <= opIndex op2+            = Just $ op2 { opIndex = opIndex op2 + (length $ opInsert op1) - opRemove op2 }++        | opIndex op2 + opRemove op2 < opIndex op1+            = Just op2++        | otherwise = Nothing++++-- | Given an 'Operation' which was created against a particular 'Value'+-- (content), rebase it on top of patches which were created against the very+-- same content in parallel.+--+-- This function assumes that the patches apply cleanly to the content.+-- Failure to do so results in a fatal error.++rebaseOperation :: Value -> Operation -> [Patch] -> Maybe Operation+rebaseOperation _       op []     = Just op+rebaseOperation content op (x:xs) = case applyOperation content (patchOperation x) of+    Left e -> error $ "Unexpected failure: " ++ (show e)+    Right newContent -> case opOT newContent (patchOperation x) op of+        Nothing  -> Nothing+        Just op' -> rebaseOperation newContent op' xs
+ src/Avers/Storage.hs view
@@ -0,0 +1,608 @@+{-# LANGUAGE BangPatterns        #-}+{-# LANGUAGE FlexibleContexts    #-}+{-# LANGUAGE OverloadedStrings   #-}+{-# LANGUAGE RecordWildCards     #-}+{-# LANGUAGE ScopedTypeVariables #-}+{-# LANGUAGE TemplateHaskell     #-}++{-|++This module abstracts the storage engine and provides functions to+manipulate objects stored in it.++-}++module Avers.Storage where++import           Control.Applicative+import           Control.Concurrent.STM++import           Control.Monad.Random (getRandomR, evalRandIO)+import           Control.Monad.State+import           Control.Monad.Except++import           Data.Char+import           Data.Monoid+import           Data.Maybe+import qualified Data.ByteString.Lazy   as BL+import qualified Data.ByteString.Base16 as BS16++import           Data.Vector        (Vector)+import qualified Data.Vector        as V++import           Data.Text          (Text)+import qualified Data.Text          as T+import qualified Data.Text.Encoding as T++import qualified Data.Map           as M++import           Data.Time+import           Data.List (find)+import           Data.Aeson (Value)+import           Data.Aeson.Types (emptyObject)++import qualified Crypto.Hash.SHA3 as SHA3++import qualified Database.RethinkDB as R++import           Crypto.Scrypt++import           Avers.Metrics+import           Avers.Types+import           Avers.Patching+import           Avers.TH+import           Avers.Views++import           Avers.Storage.Backend+import           Avers.Storage.Expressions+++requireResult :: AversError -> Maybe a -> Avers a+requireResult err Nothing  = throwError err+requireResult _   (Just v) = return v+++-- All the tables which this storage engine uses.+objectsTable, sessionsTable, snapshotsTable, patchesTable, secretsTable, blobsTable :: R.Exp R.Table+blobsTable     = R.Table Nothing $ R.lift ("blobs" :: Text)+objectsTable   = R.Table Nothing $ R.lift ("objects" :: Text)+patchesTable   = R.Table Nothing $ R.lift ("patches" :: Text)+secretsTable   = R.Table Nothing $ R.lift ("secrets" :: Text)+sessionsTable  = R.Table Nothing $ R.lift ("sessions" :: Text)+snapshotsTable = R.Table Nothing $ R.lift ("snapshots" :: Text)+++trace :: String -> Avers a -> Avers a+trace label act = do+    start <- liftIO $ getCurrentTime+    ret <- act+    end <- liftIO $ getCurrentTime++    reportPoint+        ("avers.storage." <> (T.pack label) <> ".duration")+        (realToFrac $ diffUTCTime end start)++    return ret+++-- | True if the object exists.+exists :: ObjId -> Avers Bool+exists objId = trace "exists" $+    existsDocument objectsTable (BaseObjectId objId)+++-- | Lookup an 'Object' by its 'ObjId'. Throws 'ObjectNotFound' if the object+-- doesn't exist.+lookupObject :: ObjId -> Avers Object+lookupObject objId = trace "lookupObject" $ do+    mbObject <- lookupDocument objectsTable (BaseObjectId objId)+    requireResult (ObjectNotFound objId) mbObject+++-- | Create a new object of the given type. An initial snapshot ('RevId' 0)+-- is created from the supplied content.+createObject :: (ToJSON a) => ObjectType a -> ObjId -> a -> Avers ObjId+createObject ot@ObjectType{..} createdBy content = do+    objId <- otId+    now   <- liftIO $ getCurrentTime++    let object   = Object objId otType now createdBy Nothing+        boId     = BaseObjectId objId+        snapshot = Snapshot boId zeroRevId (toJSON content)++    insertDocument objectsTable object+    insertDocument snapshotsTable snapshot++    updateObjectViews ot objId (Just content)++    return objId+++-- | Mark the object as deleted.+deleteObject :: ObjId -> Avers ()+deleteObject objId = do+    obj <- lookupObject objId+    upsertDocument objectsTable (obj { objectDeleted = Just True })++    SomeObjectType objType <- lookupObjectType (objectType obj)+    updateObjectViews objType objId Nothing++++-- | Prune the object from the database. This is only allowed if the object is+-- marked as deleted. Note that this is a very dangerous operation, it can not+-- be undone.+pruneObject :: ObjId -> Avers ()+pruneObject objId = do+    obj <- lookupObject objId+    SomeObjectType objType <- lookupObjectType (objectType obj)++    unless (objectDeleted obj == Just True) $+        strErr $ "pruneObject: object " ++ show objId ++ " is not deleted"++    -- Drop all related patches. Note that there will never be a patch with+    -- revision zero, so it's safe to use 'patchesAfterRevision'.+    patches <- patchesAfterRevision (BaseObjectId objId) zeroRevId+    void $ mapM (deleteDocument patchesTable) patches++    -- Drop all related snapshots.+    snapshotDatums <- runQueryCollect $+        R.BetweenIndexed+            "objectSnapshotSequence"+            ( R.Closed $ R.Array $ V.fromList [R.String $ toPk objId, R.Number $ fromIntegral (0 :: Int)]+            , R.Open $ R.Array $ V.fromList [R.String $ toPk objId, R.Number $ fromIntegral (99999999 :: Int)]+            )++        snapshotsTable+    snapshots <- V.mapM parseDatum snapshotDatums :: Avers (Vector Snapshot)+    void $ V.mapM (deleteDocument snapshotsTable) snapshots++    -- Remove related entries from all views.+    forM_ (otViews objType) $ \(SomeView view) -> do+        deleteDocument (viewTable view) objId++    -- Drop the object itself.+    void $ deleteDocument objectsTable objId++++-----------------------------------------------------------------------------+-- | Fetch the content of the object and try to parse it.+--+-- This function will fail with a 'ParseError' if the content can not be+-- decoded into the desired type.++objectContent :: (FromJSON a) => ObjectId -> Avers a+objectContent objId = do+    Snapshot{..} <- lookupLatestSnapshot objId+    parseValue snapshotContent++++-----------------------------------------------------------------------------+-- | Get the snapshot of the newest revision of the given object.++lookupLatestSnapshot :: ObjectId -> Avers Snapshot+lookupLatestSnapshot objId = trace "lookupLatestSnapshot" $ do+    snapshot <- newestSnapshot objId+    patches  <- patchesAfterRevision objId (snapshotRevisionId snapshot)+    applyPatches snapshot patches+++-- TODO: Verify that the patch is applicable to the snapshot, ie.+--   snapshot revId == patch revId + 1+applyPatchToSnapshot :: Snapshot -> Patch -> Avers Snapshot+applyPatchToSnapshot snapshot@Snapshot{..} Patch{..} =+    case applyOperation snapshotContent patchOperation of+        Left  e -> patchError e+        Right v -> return $ snapshot { snapshotContent    = v+                                     , snapshotRevisionId = patchRevisionId+                                     }+++applyPatches :: Snapshot -> [Patch] -> Avers Snapshot+applyPatches snapshot patches =+    foldM applyPatchToSnapshot snapshot patches+++lookupRecentRevision :: ObjectId -> Avers (Maybe RevId)+lookupRecentRevision objId = do+    m <- liftIO . atomically . readTVar =<< gets recentRevisionCache+    return $ M.lookup objId m++updateRecentRevision :: ObjectId -> RevId -> Avers ()+updateRecentRevision objId revId = do+    cache <- gets recentRevisionCache+    liftIO $ atomically $ modifyTVar' cache $+        M.insertWith max objId revId+++++-----------------------------------------------------------------------------+-- | Get the newest snapshot which is stored in the database. The object may+-- be at a higher revision if the later snapshots are missing from the+-- database.+--+-- This is an internal function. If you want the latest snapshot, you should+-- use 'lookupLatestSnapshot'.++newestSnapshot :: ObjectId -> Avers Snapshot+newestSnapshot objId = trace "newestSnapshot" $ do+    (RevId revId) <- fromMaybe zeroRevId <$> lookupRecentRevision objId+    snapshot <- runQueryDatum $ headE $+        R.OrderByIndexed (R.Descending "objectSnapshotSequence") $+        R.BetweenIndexed "objectSnapshotSequence" ((lowerBound revId), upperBound) $+        snapshotsTable++    updateRecentRevision objId (snapshotRevisionId snapshot)+    return snapshot++  where+    lowerBound revId = R.Closed $ R.Array $ V.fromList [R.String $ toPk objId, R.Number $ fromIntegral revId]+    upperBound = R.Open $ R.Array $ V.fromList [R.String $ toPk objId, R.Number $ fromIntegral (99999999 :: Int)]++++lookupSnapshot :: ObjectId -> RevId -> Avers Snapshot+lookupSnapshot objId (RevId revId) = trace "lookupSnapshot" $ do+    snapshot <- runQueryDatum $ headE $+        R.OrderByIndexed (R.Descending "objectSnapshotSequence") $+        R.BetweenIndexed "objectSnapshotSequence" (lowerBound, upperBound) $+        snapshotsTable++    -- Get all patches which we need to apply on top of the snapshot to+    -- arrive at the desired revision.+    patches0 <- patchesAfterRevision objId (snapshotRevisionId snapshot)+    let patches = filter (\Patch{..} -> patchRevisionId <= RevId revId) patches0++    foldM applyPatchToSnapshot snapshot patches++  where+    lowerBound = R.Closed $ R.Array $ V.fromList [R.String $ toPk objId, R.Number 0]+    upperBound = R.Closed $ R.Array $ V.fromList [R.String $ toPk objId, R.Number $ fromIntegral revId]++++savePatch :: Patch -> Avers ()+savePatch = insertDocument patchesTable++saveSnapshot :: Snapshot -> Avers ()+saveSnapshot = insertDocument snapshotsTable++++-----------------------------------------------------------------------------+-- Update the secret value. If a secret with the given 'SecretId' does not+-- exist yet, one will be created (IOW this function has upsert semantics).++updateSecret :: SecretId -> Text -> Avers ()+updateSecret secId secret = do+    ep <- liftIO $ encryptPassIO defaultParams (Pass $ T.encodeUtf8 secret)+    saveSecretValue secId ep++++-----------------------------------------------------------------------------+-- | Verify the value against the secret. If that fails, then this function+-- throws an error.+--+-- This function automatically updates the secret in the database if the+-- scrypt params have changed.++verifySecret :: SecretId -> Text -> Avers ()+verifySecret secId secret = do+    Secret{..} <- requireResult (DocumentNotFound $ toPk secId) =<<+        lookupDocument secretsTable secId++    let ep        = EncryptedPass $ T.encodeUtf8 secretValue+    let (ok, new) = verifyPass defaultParams (Pass $ T.encodeUtf8 secret) ep++    -- If the secret doens't match, return NotFound+    when (not ok) $ strErr $ "Not Found"++    -- Update the database if we got a new value from the verify step. This+    -- is the case when the scrypt params have changed. See documentation of+    -- 'verifyPass'.+    maybe (return ()) (saveSecretValue secId) new++++-----------------------------------------------------------------------------+-- | Internal function which actually saves a secret in the database.++saveSecretValue :: SecretId -> EncryptedPass -> Avers ()+saveSecretValue secId (EncryptedPass x) = do+   upsertDocument secretsTable $ Secret secId $ T.decodeUtf8 x+++++patchesAfterRevision :: ObjectId -> RevId -> Avers [Patch]+patchesAfterRevision objId (RevId revId) = trace "patchesAfterRevision" $ do+    res <- runQuery $+        R.OrderBy [R.Ascending "revisionId"] $+        R.BetweenIndexed "objectPatchSequence" (lowerBound, upperBound) $+        patchesTable++    V.toList <$> V.mapM parseDatum res++  where+    lowerBound = R.Open $ R.Array $ V.fromList [R.String $ toPk objId, R.Number $ fromIntegral revId]+    upperBound = R.Open $ R.Array $ V.fromList [R.String $ toPk objId, R.Number $ fromIntegral (revId + 999999)]+++lookupPatch :: ObjectId -> RevId -> Avers Patch+lookupPatch objId revId = trace "lookupPatch" $ do+    runQuerySingleSelection $ R.Get patchesTable $ R.lift $+        toPk objId <> "@" <> toPk revId++++-- | Lookup an object type which is registered in the Avers monad.+lookupObjectType :: Text -> Avers SomeObjectType+lookupObjectType objType = do+    types <- objectTypes <$> gets config+    case find (\(SomeObjectType ObjectType{..}) -> otType == objType) types of+        Nothing -> throwError $ UnknownObjectType objType+        Just x  -> return x++++applyObjectUpdates+    :: ObjectId    -- ^ The object which you want to update+    -> RevId       -- ^ The 'RevId' against which the operations were created+    -> ObjId       -- ^ Committer+    -> [Operation] -- ^ The operations to apply+    -> Bool        -- ^ True if validation should be skipped+    -> Avers ([Patch], Int, [Patch])++applyObjectUpdates objId revId committerId ops novalidate = trace "applyObjectUpdates" $ do+    -- First check that the object exists. We'll need its metadata later.+    obj <- lookupObject baseObjId+    SomeObjectType ot <- lookupObjectType (objectType obj)++    -- The 'Snapshot' against which the submitted operations were created.+    baseSnapshot <- lookupSnapshot objId revId++    -- If there are any patches which the client doesn't know about we need+    -- to let her know.+    previousPatches <- patchesAfterRevision objId revId++    latestSnapshot <- applyPatches baseSnapshot previousPatches++    -- Apply the operations and get the final snapshot.+    (Snapshot{..}, PatchState{..}) <- runStateT (patchHandler novalidate) $+        PatchState ot objId revId committerId ops 0+            baseSnapshot latestSnapshot previousPatches []++    -- Update object views.+    unless novalidate $ do+        content <- parseValue snapshotContent+        updateObjectViews ot baseObjId (Just content)++    return (previousPatches, psNumConsumedOperations, psPatches)++  where+    baseObjId = objectIdBase objId++++data PatchState a = PatchState+  { psObjectType            :: ObjectType a+  , psObjectId              :: ObjectId+  , psRevisionId            :: RevId+  , psCommitterId           :: ObjId+  , psOperations            :: [ Operation ]+  , psNumConsumedOperations :: Int+  , psBaseSnapshot          :: Snapshot+  , psLatestSnapshot        :: Snapshot+  , psPreviousPatches       :: [ Patch ]+  , psPatches               :: [ Patch ]+  }+++type AversPatch a b = StateT (PatchState a) Avers b+++patchHandler :: (FromJSON a) => Bool -> AversPatch a Snapshot+patchHandler novalidate = do+    PatchState{..} <- get+    foldM (saveOperation $ snapshotContent psBaseSnapshot)+        psLatestSnapshot psOperations++  where++    saveOperation baseContent snapshot@Snapshot{..} op = do+        PatchState{..} <- get++        case rebaseOperation baseContent op psPreviousPatches of+            Nothing -> return snapshot+            Just op' -> do+                now <- liftIO $ getCurrentTime++                let revId = succ snapshotRevisionId+                    patch = Patch psObjectId revId psCommitterId now op'++                case applyOperation snapshotContent op' of+                    Left e -> error $ "Failure: " ++ (show e)+                    Right newContent+                        | newContent /= snapshotContent -> do+                            unless novalidate $ do+                                lift $ validateWithType psObjectType newContent++                            let newSnapshot = snapshot { snapshotContent    = newContent+                                                       , snapshotRevisionId = revId+                                                       }++                            -- Now we know that the patch can be applied cleanly, so+                            -- we can save it in the database.+                            lift $ savePatch patch++                            modify $ \s -> s+                                { psPatches = psPatches ++ [patch]+                                , psNumConsumedOperations = psNumConsumedOperations + 1+                                }++                            lift $ saveSnapshot newSnapshot+                            return newSnapshot+                        | otherwise -> return snapshot+++existsBlob :: BlobId -> Avers Bool+existsBlob = existsDocument blobsTable++lookupBlob :: BlobId -> Avers Blob+lookupBlob bId = lookupDocument blobsTable bId >>=+    requireResult (DocumentNotFound $ toPk bId)++insertBlob :: Blob -> Avers ()+insertBlob = insertDocument blobsTable++saveBlobContent :: Blob -> BL.ByteString -> Avers ()+saveBlobContent Blob{..} content = do+    cfg <- gets config+    liftIO $ (putBlob cfg) blobId blobContentType content+++saveSession :: Session -> Avers ()+saveSession = insertDocument sessionsTable++lookupSession :: SessionId -> Avers Session+lookupSession sessId = lookupDocument sessionsTable sessId >>=+    requireResult (DocumentNotFound $ toPk sessId)++dropSession :: SessionId -> Avers ()+dropSession sessId = void $ deleteDocument sessionsTable sessId++++newId :: Int -> IO Text+newId n = T.pack <$> take n <$> randomAlphanumericSequence+  where+    randomAlphanumericSequence :: IO String+    randomAlphanumericSequence = map alnum <$>+        evalRandIO (sequence $ repeat $ getRandomR (0, 61))++    alnum :: Int -> Char+    alnum x+        | x < 26 = chr ((x     ) + 65)+        | x < 52 = chr ((x - 26) + 97)+        | x < 62 = chr ((x - 52) + 48)+        | otherwise = error $ "Out of range: " ++ show x+++validateObject :: Text -> Value -> Avers ()+validateObject objType value = do+    (SomeObjectType ot) <- lookupObjectType objType+    validateWithType ot value++validateWithType :: (FromJSON a) => ObjectType a -> Value -> Avers ()+validateWithType ot value = case parseValueAs ot value of+    Left e  -> throwError e+    Right _ -> return ()+++lookupRelease :: ObjId -> RevId -> Avers Release+lookupRelease objId revId = objectContent (ReleaseObjectId objId revId)+++-- | Create a new release of the given revision. If the object doesn't exist,+-- it will fail with 'ObjectNotFound'.+createRelease :: ObjId -> RevId -> Avers ()+createRelease objId revId = do+    -- The object must exist.+    objectExists <- exists objId+    unless objectExists $ throwError (ObjectNotFound objId)++    -- The release objects are not patchable at the moment. If one already+    -- exists, then there is nothing to do. Otherwise create the initial+    -- snapshot with empty content.+    exists' <- existsDocument snapshotsTable (toPk snapshot)+    unless exists' $ insertDocument snapshotsTable snapshot++  where+    objectId = ReleaseObjectId objId revId+    snapshot = Snapshot objectId zeroRevId emptyObject+++lookupLatestRelease :: ObjId -> Avers (Maybe RevId)+lookupLatestRelease objId = do+    let match = R.lift $ "^" <> toPk objId <> "/release/"++        predicate :: R.Exp R.Object -> R.Exp Bool+        predicate x = R.Coerce+            (R.Match (objectFieldE "objectId" x) match)+            (R.lift ("bool"::Text))++    oId <- runQueryDatum $+        (objectFieldE "objectId" :: R.Exp R.Object -> R.Exp R.Datum) $+        headE $+        R.OrderBy [R.Descending "objectId"] $+        R.Filter predicate snapshotsTable++    case oId of+        ReleaseObjectId objId1 revId -> do+            when (objId /= objId1) $ databaseError "lookupLatestRelease: objId do not match"+            return $ Just revId++        _ -> return Nothing++++-------------------------------------------------------------------------+-- Blobs+-------------------------------------------------------------------------++createBlob :: BL.ByteString -> Text -> Avers Blob+createBlob body contentType = do+    -- Only create the blob if it doesn't already exist. That way we can+    -- avoid having to upload the blob to the storage.+    ex <- existsBlob (blobId blob)+    unless ex $ do+        saveBlobContent blob body+        insertBlob blob++    return blob++  where+    size = fromIntegral $ BL.length body+    hash = BS16.encode $ SHA3.hashlazy 256 body+    blob = Blob (BlobId $ T.decodeUtf8 hash) size contentType+++objectsOfType :: ObjectType a -> Avers (Vector ObjId)+objectsOfType objType = do+    let predicate :: R.Exp R.Object -> R.Exp Bool+        predicate = objectFieldEqE "type" (otType objType)++    res <- runQueryCollect $+        R.Map mapId $+        R.OrderBy [R.Descending "createdAt", R.Ascending "id"] $+        R.Filter isNotDeleted $+        R.Filter predicate objectsTable++    return $ V.map ObjId res+++allObjectsOfType :: ObjectType a -> Avers (Vector ObjId)+allObjectsOfType objType = do+    let predicate :: R.Exp R.Object -> R.Exp Bool+        predicate = objectFieldEqE "type" (otType objType)++    res <- runQueryCollect $+        R.Map mapId $+        R.OrderBy [R.Descending "createdAt", R.Ascending "id"] $+        R.Filter predicate objectsTable++    return $ V.map ObjId res+++isNotDeleted :: R.Exp R.Object -> R.Exp Bool+isNotDeleted x = R.Any+    [ R.Not $ R.HasFields ["deleted"] x+    , objectFieldEqE "deleted" False x+    ]++mapId:: R.Exp R.Object -> R.Exp Text+mapId = R.GetField "id"
+ src/Avers/Storage/Backend.hs view
@@ -0,0 +1,159 @@+{-# LANGUAGE FlexibleContexts  #-}+{-# LANGUAGE OverloadedStrings #-}+{-# LANGUAGE RecordWildCards   #-}+{-# LANGUAGE TemplateHaskell   #-}+{-# LANGUAGE TypeFamilies      #-}+++{-|++Low-level implementation of the storage backend.++-}++module Avers.Storage.Backend+  ( parseValue+  , parseDatum++  , runQuery+  , runQueryDatum+  , runQuerySingleSelection+  , runQueryCollect++  , existsDocument+  , lookupDocument+  , insertDocument+  , upsertDocument+  , deleteDocument+  ) where+++import           Prelude hiding (lookup)++import           Control.Monad.Except+import           Control.Monad.State++import           Data.Monoid+import           Data.Aeson (Value, Result(..))+import           Data.Aeson.Types (parse, parseEither)+import           Data.Pool+import qualified Data.Text as T+import qualified Data.HashMap.Strict as HMS+import qualified Data.Vector as V++import qualified Database.RethinkDB       as R+import           Database.RethinkDB.TH++import           Avers.TH+import           Avers.Types+import           Avers.Storage.Expressions++++parseValue :: (FromJSON a, MonadError AversError m) => Value -> m a+parseValue value = case parseEither parseJSON value of+    Left  e -> parseError value (T.pack e)+    Right x -> return x+++parseDatum :: (R.FromDatum a, MonadError AversError m) => R.Datum -> m a+parseDatum datum = case parse R.parseDatum datum of+    Error e -> parseError (toJSON datum) (T.pack e)+    Success x -> return x++++data WriteResponse = WriteResponse+  { writeResponseInserted  :: Int+  , writeResponseDeleted   :: Int+  , writeResponseReplaced  :: Int+  , writeResponseUnchanged :: Int+  , writeResponseSkipped   :: Int+  , writeResponseErrors    :: Int+  } deriving (Show)+++checkWriteResponse :: Maybe R.Datum -> Avers ()+checkWriteResponse resp = do+    case resp of+        Nothing -> strErr "Error"+        Just x ->+            case parseEither R.parseDatum x of+                Left err -> strErr err+                Right WriteResponse{..} ->+                    if writeResponseErrors == 0+                        then return ()+                        else databaseError $ "Errors during write operation: " <> T.pack (show resp)++mergePk :: (R.ToDatum a, Pk a) => a -> R.Object+mergePk doc = HMS.insert primaryKeyField (R.String $ toPk doc) hms+  where (R.Object hms) = R.toDatum doc+++runQuerySingleSelection :: (R.FromDatum a) => R.Exp R.SingleSelection -> Avers a+runQuerySingleSelection query = do+    res <- runQuery query+    case res of+        Nothing -> documentNotFound "..."+        Just x  -> parseDatum x++runQueryDatum :: (R.FromDatum a) => R.Exp R.Datum -> Avers a+runQueryDatum query = do+    res <- runQuery query+    parseDatum res++runQuery :: (R.FromResponse (R.Result a)) => R.Exp a -> Avers (R.Result a)+runQuery query = do+    pool <- gets databaseHandlePool+    res <- liftIO $ withResource pool $ \handle -> do+        R.run handle query++    case res of+        Left e -> databaseError (T.pack $ show e)+        Right r -> return r++runQueryCollect :: (R.FromDatum a, R.IsSequence e, R.Result e ~ R.Sequence a) => R.Exp e -> Avers (V.Vector a)+runQueryCollect query = do+    pool <- gets databaseHandlePool+    res <- liftIO $ withResource pool $ \handle -> do+        r0 <- R.run handle query+        case r0 of+            Left e -> return $ Left e+            Right x -> R.collect handle x++    case res of+        Left e -> databaseError (T.pack $ show e)+        Right r -> return r++++existsDocument :: (Pk k) => R.Exp R.Table -> k -> Avers Bool+existsDocument table key = do+    res <- runQuery $ R.IsEmpty $ R.Filter (primaryKeyEqE (toPk key)) table+    return $ not res+++lookupDocument :: (Pk k, R.FromDatum a) => R.Exp R.Table -> k -> Avers (Maybe a)+lookupDocument table key = do+    res <- runQuery $ R.Get table (R.lift (toPk key))+    maybe (return Nothing) parseDatum res+++insertDocument :: (R.ToDatum a, Pk a) => R.Exp R.Table -> a -> Avers ()+insertDocument table doc = do+    resp <- runQuery $ R.InsertObject R.CRError table (mergePk doc)+    checkWriteResponse $ Just $ R.Object resp+++deleteDocument :: (Pk k) => R.Exp R.Table -> k -> Avers ()+deleteDocument table key = do+    resp <- runQuery $ R.Delete $ R.Get table (R.lift $ toPk key)+    checkWriteResponse $ Just $ R.Object resp+++upsertDocument :: (R.ToDatum a, Pk a) => R.Exp R.Table -> a -> Avers ()+upsertDocument table doc = do+    resp <- runQuery $ R.InsertObject R.CRReplace table (mergePk doc)+    checkWriteResponse $ Just $ R.Object resp++$(deriveDatum (deriveJSONOptions "writeResponse") ''WriteResponse)
+ src/Avers/Storage/Expressions.hs view
@@ -0,0 +1,52 @@+{-# LANGUAGE FlexibleContexts  #-}+{-# LANGUAGE OverloadedStrings #-}+{-# LANGUAGE RecordWildCards   #-}+{-# LANGUAGE TemplateHaskell   #-}+{-# LANGUAGE TypeFamilies      #-}+++{-|++This module contains RethinkDB Expressions which are used to build queries.++-}++module Avers.Storage.Expressions where+++import           Prelude hiding (lookup)++import           Data.Text (Text)+import           Database.RethinkDB as R+++-- | The primary key in all our documents is the default "id".+primaryKeyField :: Text+primaryKeyField = "id"+++-- | Expression which represents the primary key field.+primaryKeyFieldE :: Exp Text+primaryKeyFieldE = lift primaryKeyField+++-- | Expression which represents the value of a field inside of an Object.+objectFieldE :: (IsDatum a) => Text -> Exp Object -> Exp a+objectFieldE field obj = GetField (lift field) obj+++-- | True if the object field matches the given value.+objectFieldEqE :: (ToDatum a) => Text -> a -> Exp Object -> Exp Bool+objectFieldEqE field value obj = Eq+    (objectFieldE field obj :: Exp Datum)+    (lift $ toDatum value)+++-- | True if the object's primary key matches the given string.+primaryKeyEqE :: Text -> Exp Object -> Exp Bool+primaryKeyEqE = objectFieldEqE primaryKeyField+++-- | Take the first item out of a sequence.+headE :: (IsSequence a, IsDatum r) => Exp a -> Exp r+headE = Nth 0
+ src/Avers/TH.hs view
@@ -0,0 +1,234 @@+{-# LANGUAGE TemplateHaskell #-}++module Avers.TH+  ( deriveJSON+  , deriveJSONOptions+  , variantOptions+  , defaultVariantOptions++  , deriveEncoding+  , deriveRecordEncoding++  , FromJSON(..)+  , ToJSON(..)+  ) where+++import           Language.Haskell.TH++import           Control.Applicative+import           Control.Monad++import           Data.Char++import qualified Data.HashMap.Strict as HM+import qualified Data.Text           as T++import           Data.Aeson+import           Data.Aeson.TH+import qualified Data.Aeson.Types as A++import           Text.Inflections++import qualified Database.RethinkDB as R+import           Database.RethinkDB (toDatum, FromDatum(..))+import           Database.RethinkDB.TH++++dropPrefix :: String -> String -> String+dropPrefix prefix x = toLower (head rest) : tail rest+  where rest = drop (length prefix) x+++-- FIXME: Should dasherize and drop the prefix from the constructor as well!+deriveJSONOptions :: String -> Options+deriveJSONOptions prefix = defaultOptions+    { fieldLabelModifier     = dropPrefix prefix+    , constructorTagModifier = map toLower+    }++dasherizeTag :: String -> String+dasherizeTag x = case parseCamelCase [] x of+    Left  err -> error $ show err+    Right res -> map toLower $ dasherize res++variantOptions :: String -> String -> String -> Options+variantOptions tagField contentsField prefix = defaultOptions+    { constructorTagModifier = dasherizeTag . dropPrefix prefix+    , sumEncoding            = TaggedObject tagField contentsField+    }++defaultVariantOptions :: String -> Options+defaultVariantOptions = variantOptions "type" "content"+++deriveEncoding :: Options -> Name -> Q [Dec]+deriveEncoding opts name =+    liftM2 (++)+        (deriveJSON opts name)+        (deriveDatum opts name)+++deriveEncodingWithDefaults :: Options -> Name -> [(String, Q Exp)] -> Q [Dec]+deriveEncodingWithDefaults options typeN defaults =+    liftM2 (++)+        (deriveJSONWithDefaults options typeN defaults)+        (deriveDatumWithDefaults options typeN defaults)+++deriveRecordEncoding :: Name -> String -> [(String, Q Exp)] -> Q [Dec]+deriveRecordEncoding typeN prefix defaults =+    deriveEncodingWithDefaults (deriveJSONOptions prefix) typeN defaults++++------------------------------------------------------------------------------+-- JSON++deriveJSONWithDefaults :: Options -> Name -> [(String, Q Exp)] -> Q [Dec]+deriveJSONWithDefaults options typeN defaults = liftM2 (++)+    (deriveToJSON options typeN)+    (deriveFromJSONWithDefaults options typeN defaults)++deriveFromJSONWithDefaults :: Options -> Name -> [(String, Q Exp)] -> Q [Dec]+deriveFromJSONWithDefaults options typeN defaults = do+    xN                        <- newName "x"+    (tyVarsBndrs, fieldNames) <- getTyInfo typeN+    parseJsonE                <- mkParseJSON options typeN+    insertDefaultsE           <- mkInsertDefaults defaults+    modifyObjectE             <- [|modifyObject|]+    let tyVars      = tyVarBndrNames tyVarsBndrs+        fieldNames' = map (fieldLabelModifier options . nameBase) fieldNames++    forM_ defaults $ \(name, _) ->+        when (name `notElem` fieldNames') $ fail $+            "Avers.TH.deriveFromJSONWithDefaults: default " +++            "specified for " ++ show name ++ " but this field does not exist."++    return+        [ InstanceD [ClassP ''FromJSON [VarT tv] | tv <- tyVars]+            (AppT fromJsonT (mkAppTys (typeT : map VarT tyVars)))+            [ FunD 'parseJSON+                [ Clause [VarP xN]+                    (NormalB (AppE parseJsonE (mkApps+                        [modifyObjectE, insertDefaultsE, VarE xN])))+                    []+                ]+            ]+        ]+  where+    typeT     = ConT typeN+    fromJsonT = ConT ''FromJSON++modifyObject :: (A.Object -> A.Object) -> A.Value -> A.Value+modifyObject f (A.Object o) = A.Object (f o)+modifyObject _ v            = v+{-# INLINE modifyObject #-}++mkInsertDefaults :: [(String, Q Exp)] -> Q Exp+mkInsertDefaults defaults = do+    yN    <- newName "y"+    bodyE <- foldM insertDefault (VarE yN) defaults+    return $ LamE [VarP yN] bodyE+  where+    flipE       = VarE 'flip+    constE      = VarE 'const+    insertWithE = VarE 'HM.insertWith+    toJsonE     = VarE 'toJSON++    insertDefault hmE (field, expQ) = do+        textE    <- [|T.pack field|]+        defaultE <- expQ+        return $ mkApps [insertWithE, AppE flipE constE,+                textE, AppE toJsonE defaultE, hmE]+++------------------------------------------------------------------------------+-- Datum++deriveDatumWithDefaults :: Options -> Name -> [(String, Q Exp)] -> Q [Dec]+deriveDatumWithDefaults options typeN defaults = liftM2 (++)+    (deriveToDatum options typeN)+    (deriveFromDatumWithDefaults options typeN defaults)++deriveFromDatumWithDefaults :: Options -> Name -> [(String, Q Exp)] -> Q [Dec]+deriveFromDatumWithDefaults options typeN defaults = do+    xN                        <- newName "x"+    (tyVarsBndrs, fieldNames) <- getTyInfo typeN+    parseJsonE                <- mkParseDatum options typeN+    insertDefaultsE           <- mkInsertDatumDefaults defaults+    modifyObjectE             <- [|modifyDatumObject|]+    let tyVars      = tyVarBndrNames tyVarsBndrs+        fieldNames' = map (fieldLabelModifier options . nameBase) fieldNames++    forM_ defaults $ \(name, _) ->+        when (name `notElem` fieldNames') $ fail $+            "Avers.TH.deriveFromDatumWithDefaults: default " +++            "specified for " ++ show name ++ " but this field does not exist."++    return+        [ InstanceD [ClassP ''FromDatum [VarT tv] | tv <- tyVars]+            (AppT fromDatumT (mkAppTys (typeT : map VarT tyVars)))+            [ FunD 'parseDatum+                [ Clause [VarP xN]+                    (NormalB (AppE parseJsonE (mkApps+                        [modifyObjectE, insertDefaultsE, VarE xN])))+                    []+                ]+            ]+        ]+  where+    typeT      = ConT typeN+    fromDatumT = ConT ''FromDatum++modifyDatumObject :: (R.Object -> R.Object) -> R.Datum -> R.Datum+modifyDatumObject f (R.Object o) = R.Object (f o)+modifyDatumObject _ v            = v+{-# INLINE modifyDatumObject #-}++mkInsertDatumDefaults :: [(String, Q Exp)] -> Q Exp+mkInsertDatumDefaults defaults = do+    yN    <- newName "y"+    bodyE <- foldM insertDefault (VarE yN) defaults+    return $ LamE [VarP yN] bodyE+  where+    flipE       = VarE 'flip+    constE      = VarE 'const+    insertWithE = VarE 'HM.insertWith+    toJsonE     = VarE 'toDatum++    insertDefault hmE (field, expQ) = do+        textE    <- [|T.pack field|]+        defaultE <- expQ+        return $ mkApps [insertWithE, AppE flipE constE,+                textE, AppE toJsonE defaultE, hmE]++++mkApps :: [Exp] -> Exp+mkApps = foldl1 AppE++mkAppTys :: [Type] -> Type+mkAppTys = foldl1 AppT++getTyInfo :: Name -> Q ([TyVarBndr], [Name])+getTyInfo typeN = do+    info <- reify typeN+    case info of+        TyConI (DataD _ _ tvbs cons _)   -> pure (tvbs, getFieldNames =<< cons)+        TyConI (NewtypeD _ _ tvbs con _) -> pure (tvbs, getFieldNames con)+        _                                -> fail $+            "Avers.TH.getTyInfo: only simple data/newtype " +++            "constructors are supported."++tyVarBndrNames :: [TyVarBndr] -> [Name]+tyVarBndrNames = map $ \tvb -> case tvb of+    PlainTV  n   -> n+    KindedTV n _ -> n++getFieldNames :: Con -> [Name]+getFieldNames (NormalC _ _)     = []+getFieldNames (InfixC _ _ _)    = []+getFieldNames (ForallC _ _ con) = getFieldNames con+getFieldNames (RecC _ fields)   = [name | (name, _, _) <- fields]
+ src/Avers/Types.hs view
@@ -0,0 +1,604 @@+{-# LANGUAGE FlexibleContexts           #-}+{-# LANGUAGE GADTs                      #-}+{-# LANGUAGE GeneralizedNewtypeDeriving #-}+{-# LANGUAGE OverloadedStrings          #-}+{-# LANGUAGE RecordWildCards            #-}+{-# LANGUAGE TemplateHaskell            #-}++module Avers.Types where++import           Control.Applicative++import           Control.Monad.Except+import           Control.Monad.State++import           Control.Concurrent.STM++import           Data.Time.Clock+import           Data.String+import           Data.ByteString.Lazy (ByteString)++import           Data.Text (Text)+import qualified Data.Text as T++import           Data.Map  (Map)+import qualified Data.Map  as M++import           Data.Monoid+import           Data.Char++import           Data.Attoparsec.Text++import qualified Data.Aeson as Aeson+import qualified Data.Aeson.Types as Aeson+import           Data.Aeson (Value(String))+import           Data.Aeson.Types (parseEither)++import qualified Database.RethinkDB       as R+import           Database.RethinkDB.TH++import qualified Database.InfluxDB        as InfluxDB++import           Data.Pool++import           Avers.TH+import           Avers.Index++++-----------------------------------------------------------------------------+-- | Pk - Types which can be converted to a database primary key.++class Pk a where+    toPk :: a -> Text++instance Pk Text where+    toPk = id++++-----------------------------------------------------------------------------+-- | Path++newtype Path = Path { unPath :: Text }+    deriving (Eq, Ord, Show)++instance IsString Path where+    fromString = Path . T.pack++instance ToJSON Path where+    toJSON = toJSON . unPath++instance FromJSON Path where+    parseJSON (String s) = return $ Path s+    parseJSON _          = fail "Path"++instance R.FromDatum Path where+    parseDatum (R.String s) = return $ Path s+    parseDatum _            = fail "Path"++instance R.ToDatum Path where+    toDatum = R.toDatum . unPath++++-----------------------------------------------------------------------------+-- | ObjId++newtype ObjId = ObjId { unObjId :: Text }+    deriving (Eq, Ord, Show)++instance Pk ObjId where+    toPk = unObjId++instance ToJSON ObjId where+    toJSON = toJSON . unObjId++instance FromJSON ObjId where+    parseJSON x = ObjId <$> parseJSON x++instance R.FromDatum ObjId where+    parseDatum x = ObjId <$> R.parseDatum x++instance R.ToDatum ObjId where+    toDatum = R.toDatum . unObjId+++-- | The root object id is used for object created internally or when there+-- is no applicable creator.+rootObjId :: ObjId+rootObjId = ObjId ""++++-----------------------------------------------------------------------------+-- | RevId++newtype RevId = RevId { unRevId :: Int }+    deriving (Eq, Ord, Show)++instance Enum RevId where+    succ (RevId x) = RevId (succ x)+    pred (RevId x) = RevId (pred x)+    toEnum         = RevId+    fromEnum       = unRevId++instance Pk RevId where+    toPk = T.pack . show . unRevId++instance ToJSON RevId where+    toJSON = toJSON . unRevId++instance FromJSON RevId where+    parseJSON x = RevId <$> parseJSON x++instance R.FromDatum RevId where+    parseDatum x = RevId <$> R.parseDatum x++instance R.ToDatum RevId where+    toDatum = R.toDatum . unRevId+++-- | The 'RevId' which is used for the initial snapshot.+zeroRevId :: RevId+zeroRevId = RevId 0++++-----------------------------------------------------------------------------+-- | ObjectId++data ObjectId++    = BaseObjectId !ObjId+      -- ^ The base object whose snapshots contain the actual content.++    | ReleaseObjectId !ObjId !RevId+     -- ^ An object describing a particualar release of the base object.++    | AuthorizationObjectId !ObjId+      -- ^ Object which contains authorization rules.++    deriving (Eq, Ord, Show)+++instance Pk ObjectId where+    toPk (BaseObjectId objId)          = toPk objId+    toPk (ReleaseObjectId objId revId) = toPk objId <> "/release/" <> toPk revId+    toPk (AuthorizationObjectId objId) = toPk objId <> "/authorization"++instance ToJSON ObjectId where+    toJSON = toJSON . toPk++instance FromJSON ObjectId where+    parseJSON (String x) = either fail return $ parseOnly objectIdParser x+    parseJSON _          = fail "ObjectId"++instance R.FromDatum ObjectId where+    parseDatum (R.String x) = either fail return $ parseOnly objectIdParser x+    parseDatum _            = fail "ObjectId"++instance R.ToDatum ObjectId where+    toDatum = R.toDatum . toPk+++objectIdParser :: Parser ObjectId+objectIdParser = (releaseObjectId <|> authorizationObjectId <|> baseObjectId) <* endOfInput+  where+    objId = ObjId <$> takeWhile1 isAlphaNum+    revId = RevId <$> decimal++    baseObjectId = BaseObjectId+        <$> objId++    releaseObjectId = ReleaseObjectId+        <$> objId+        <*  string "/release/"+        <*> revId++    authorizationObjectId = AuthorizationObjectId+        <$> objId+        <*  string "/authorization"+++parseObjectId :: Text -> Maybe ObjectId+parseObjectId text = case parseOnly objectIdParser text of+    Left _  -> Nothing+    Right v -> Just v+++objectIdBase :: ObjectId -> ObjId+objectIdBase (BaseObjectId          objId  ) = objId+objectIdBase (ReleaseObjectId       objId _) = objId+objectIdBase (AuthorizationObjectId objId  ) = objId++++-----------------------------------------------------------------------------+-- | The operations that can be applied to JSON values.+data Operation+  -- | Set is applied to 'Object's. It is used for adding, updating+  --   and deleting properties from the object.+  = Set+    { opPath  :: !Path+    , opValue :: !(Maybe Value)+    }++  -- | Splice is used to manipulate 'Array's. It can remove and insert+  --   multiple elements in a single operation.+  | Splice+    { opPath   :: !Path+    , opIndex  :: !Int+    , opRemove :: !Int+    , opInsert :: ![ Value ]+    }++    deriving (Eq, Show)++$(deriveEncoding (deriveJSONOptions "op"){+    omitNothingFields = True,+    sumEncoding       = TaggedObject "type" "content"+} ''Operation)++++data PatchError+    = UnknownPatchError !Text+    deriving (Show)++type PatchM a = Either PatchError a+++data Object = Object+  { objectId            :: !ObjId+  , objectType          :: !Text+  , objectCreatedAt     :: !UTCTime+  , objectCreatedBy     :: !ObjId+  , objectDeleted       :: !(Maybe Bool)+  } deriving (Show)++instance Pk Object where+    toPk = toPk . objectId++$(deriveEncoding (deriveJSONOptions "object") ''Object)++++-----------------------------------------------------------------------------+-- | Patch++data Patch = Patch+  { patchObjectId       :: !ObjectId+  , patchRevisionId     :: !RevId+  , patchAuthorId       :: !ObjId+  , patchCreatedAt      :: !UTCTime+  , patchOperation      :: !Operation+  } deriving (Show)++instance Pk Patch where+    toPk Patch{..} = toPk patchObjectId <> "@" <> toPk patchRevisionId++$(deriveEncoding (deriveJSONOptions "patch") ''Patch)++++-----------------------------------------------------------------------------+-- | Snapshot++data Snapshot = Snapshot+  { snapshotObjectId    :: !ObjectId+  , snapshotRevisionId  :: !RevId+  , snapshotContent     :: !Value+  } deriving (Show)++instance Pk Snapshot where+    toPk Snapshot{..} = toPk snapshotObjectId <> "@" <> toPk snapshotRevisionId++$(deriveEncoding (deriveJSONOptions "snapshot") ''Snapshot)++++-----------------------------------------------------------------------------+-- | Release++data Release = Release++instance ToJSON Release where+    toJSON = const Aeson.emptyObject++instance FromJSON Release where+    parseJSON (Aeson.Object _) = return Release+    parseJSON _                = fail "Release"++-- $(deriveEncoding (deriveJSONOptions "release") ''Release)++++-----------------------------------------------------------------------------+-- | SecretId++newtype SecretId = SecretId { unSecretId :: Text }+    deriving (Show)++instance Pk SecretId where+    toPk = unSecretId++instance ToJSON SecretId where+    toJSON = toJSON . unSecretId++instance FromJSON SecretId where+    parseJSON x = SecretId <$> parseJSON x++instance R.FromDatum SecretId where+    parseDatum x = SecretId <$> R.parseDatum x++instance R.ToDatum SecretId where+    toDatum = R.toDatum . unSecretId++++-----------------------------------------------------------------------------+-- | Secret++data Secret = Secret+  { secretId    :: !SecretId+  , secretValue :: !Text+  }++instance Pk Secret where+    toPk = toPk . secretId++$(deriveEncoding (deriveJSONOptions "secret") ''Secret)++++-----------------------------------------------------------------------------+-- | BlobId++newtype BlobId = BlobId { unBlobId :: Text }+    deriving (Show)++instance Pk BlobId where+    toPk = unBlobId++instance ToJSON BlobId where+    toJSON = toJSON . unBlobId++instance FromJSON BlobId where+    parseJSON x = BlobId <$> parseJSON x++instance R.FromDatum BlobId where+    parseDatum x = BlobId <$> R.parseDatum x++instance R.ToDatum BlobId where+    toDatum = R.toDatum . unBlobId++++-----------------------------------------------------------------------------+-- | Blob++data Blob = Blob+  { blobId          :: !BlobId+  , blobSize        :: !Int+  , blobContentType :: !Text+  } deriving (Show)++instance Pk Blob where+    toPk = toPk . blobId++$(deriveEncoding (deriveJSONOptions "blob") ''Blob)++++-----------------------------------------------------------------------------+-- | SessionId++newtype SessionId = SessionId { unSessionId :: Text }++instance Pk SessionId where+    toPk = unSessionId++instance ToJSON SessionId where+    toJSON = toJSON . unSessionId++instance FromJSON SessionId where+    parseJSON x = SessionId <$> parseJSON x++instance R.FromDatum SessionId where+    parseDatum x = SessionId <$> R.parseDatum x++instance R.ToDatum SessionId where+    toDatum = R.toDatum . unSessionId++++-----------------------------------------------------------------------------+-- | The record that is stored in the database.++data Session = Session+  { sessionId             :: !SessionId+  , sessionAccountId      :: !ObjId+  , sessionCreatedAt      :: !UTCTime+  , sessionLastAccessedAt :: !UTCTime+  }++instance Pk Session where+    toPk Session{..} = toPk sessionId++$(deriveEncoding (deriveJSONOptions "session") ''Session)++++data AversError+    = InternalError !AversError+    | DatabaseError !Text+    | PatchError !PatchError+    | ParseError !Value !Text+    | UnknownObjectType !Text+    | ObjectNotFound !ObjId+    | DocumentNotFound !Text+    | AversError !Text+    | NotAuthorized+    deriving (Show)+++internalError :: AversError -> Avers a+internalError = throwError . InternalError++internal :: Avers a -> Avers a+internal m = m `catchError` internalError++databaseError :: Text -> Avers a+databaseError = throwError . DatabaseError++patchError :: PatchError -> Avers a+patchError = throwError . PatchError++parseError :: (MonadError AversError m) => Value -> Text -> m a+parseError value text = throwError $ ParseError value text++documentNotFound :: Text -> Avers a+documentNotFound = throwError . DocumentNotFound++strErr :: String -> Avers a+strErr = throwError . AversError . T.pack+++-- | An 'ObjectType' describes a particular type of object that is managed by+-- Avers.+data ObjectType a = ObjectType+  { otType   :: !Text+    -- ^ The value of the @type@ field of the 'Object'.++  , otId     :: Avers ObjId+    -- ^ Action which generates a new id. This is so that object types can+    -- have different strategies how to generate ids.++  , otViews :: [SomeView a]+  }++data SomeObjectType where+     SomeObjectType :: (R.ToDatum a, R.FromDatum a, FromJSON a, ToJSON a)+        => ObjectType a -> SomeObjectType++parseValueAs :: (FromJSON a) => ObjectType a -> Value -> Either AversError a+parseValueAs ObjectType{..} value = case parseEither parseJSON value of+    Left  e -> parseError value (T.pack $ show e)+    Right x -> return x++++-- | Configuration of the 'Avers' monad.+data AversConfig = AversConfig++    { databaseHost :: !Text+      -- ^ The hostname where RethinkDB is running. The port is currently not+      -- configurable.++    , databaseName :: !Text+      -- ^ RethinkDB supports multiple databases. This is the name of the one+      -- which should be used.++    , influxConfig :: !(Maybe InfluxDB.Config)+      -- ^ The influx server where avers reports metrics to.++    , putBlob :: BlobId -> Text -> ByteString -> IO ()+      -- ^ Function which saves the given blob in the blob store. This can be+      -- the local filesystem or an external services such as Amazon S3.+      --+      -- TODO: Propagate errors back to the caller.++    , objectTypes :: ![SomeObjectType]+      -- ^ All the object types which Avers knows about.+    }+++data AversState = AversState+    { config :: !AversConfig+      -- ^ A reference to the config, just in case we need it.++    , databaseHandlePool :: !(Pool R.Handle)+      -- ^ A pool of handles which are used to access the database.++    , recentRevisionCache :: !(TVar (Map ObjectId RevId))+      -- ^ Map from 'ObjectId' to a recent 'RevId'. It may be the latest or+      -- a few revisions behind.+    }++++newDatabaseHandlePool :: AversConfig -> IO (Pool R.Handle)+newDatabaseHandlePool AversConfig{..} =+    createPool create destroy numStripes idleTime maxResources++  where+    create = do+        putStrLn $ mconcat+            [ "Creating a new RethinkDB handle to "+            , T.unpack databaseHost+            , ":28015"+            , " database "+            , T.unpack databaseName+            ]++        R.newHandle databaseHost 28015 Nothing (R.Database (R.lift databaseName))++    destroy handle = do+        putStrLn "Closing RethinkDB handle"+        R.close handle++    numStripes   = 1+    idleTime     = fromIntegral $ (60 * 60 :: Int)+    maxResources = 10+++newState :: AversConfig -> IO AversState+newState config = do+    AversState+        <$> pure config+        <*> newDatabaseHandlePool config+        <*> newTVarIO M.empty+++newtype Avers a = Avers+    { runAvers :: StateT AversState (ExceptT AversError IO) a+    } deriving (Functor, Applicative, Monad, MonadIO, MonadError AversError, MonadState AversState)++class (Monad m) => MonadAvers m where+    liftAvers :: Avers a -> m a++instance MonadAvers Avers where+    liftAvers = id++instance MonadAvers m => MonadAvers (StateT s m) where+    liftAvers = lift . liftAvers++evalAvers :: AversState -> Avers a -> IO (Either AversError a)+evalAvers h m = runExceptT $ evalStateT (runAvers m) h++++------------------------------------------------------------------------------+-- View++data View obj a = View+  { viewName :: Text+    -- ^ The table name is derived from the view name. Therefore it should+    -- be unique amongst all views.++  , viewParser :: R.Datum -> Either AversError a+    -- ^ Function which parses objects stored in this view.++  , viewObjectTransformer :: obj -> Avers (Maybe a)+    -- ^ Function which transforms an Avers Object into a type stored+    -- in the view.++  , viewIndices :: [Index]+    -- ^ Secondary indices defined on the view.+  }+++data SomeView obj where+     SomeView :: (R.ToDatum a, R.FromDatum a, FromJSON obj, ToJSON a)+        => View obj a -> SomeView obj
+ src/Avers/Views.hs view
@@ -0,0 +1,66 @@+{-# LANGUAGE FlexibleContexts           #-}+{-# LANGUAGE GADTs                      #-}+{-# LANGUAGE GeneralizedNewtypeDeriving #-}+{-# LANGUAGE OverloadedStrings          #-}+{-# LANGUAGE RecordWildCards            #-}+{-# LANGUAGE TemplateHaskell            #-}++module Avers.Views where+++import           Control.Monad++import           Data.Aeson as Aeson+import           Data.Monoid+import qualified Data.HashMap.Strict as HMS++import qualified Database.RethinkDB as R++import           Avers.Types+import           Avers.Storage.Backend++++-- | Construct the table name for the given view. The table names look+-- something like this: "view_openGames"+viewTable :: View obj a -> R.Exp R.Table+viewTable View{..} = R.Table Nothing $ R.lift $ mconcat+    [ "view_"+    , viewName+    ]+++data Record a = Record+    { recId      :: ObjId+    , recContent :: a+    }++instance Pk (Record a) where+    toPk = toPk . recId++instance (ToJSON a) => ToJSON (Record a) where+    toJSON Record{..} = Aeson.Object $ HMS.insert "id" (Aeson.String $ toPk recId) hms+      where (Aeson.Object hms) = toJSON recContent++instance (R.ToDatum a) => R.ToDatum (Record a) where+    toDatum Record{..} = R.Object $ HMS.insert "id" (R.String $ toPk recId) $+        HMS.fromList $ map (\(k,v) -> (k, R.toDatum v)) $ HMS.toList hms+      where (R.Object hms) = R.toDatum recContent++++updateObjectViews :: ObjectType a -> ObjId -> Maybe a -> Avers ()+updateObjectViews ObjectType{..} objId mbObj = do+    forM_ otViews $ \(SomeView view) -> do+        updateView view objId mbObj+++updateView :: (R.ToDatum a) => View obj a -> ObjId -> Maybe obj -> Avers ()+updateView view@View{..} objId mbObj = do+    case mbObj of+        Nothing  -> deleteDocument (viewTable view) objId+        Just obj -> do+            mbRecord <- viewObjectTransformer obj+            case mbRecord of+                Nothing  -> deleteDocument (viewTable view) objId+                Just rec -> upsertDocument (viewTable view) (Record objId rec)